Last update Aug. 6, 2021


Low Risk

Moderately safe. Probably compatible. Mild risk possible. Follow up recommended. Read the Comment.

Sulphamide similar to sulfamethoxazole.
It remains in the intestine without being absorbed; only 5% does so in the form of sulfathiazole.
It is used together with other antibacterials in the treatment of intestinal infections and in intestinal decontamination prior to surgery.

At the date of the last update, the authors did not find any published data on the excretion of sulfathiazole in breast milk.

Sulphamides are excreted in small amounts in breast milk: 6 to 94 micrograms/ml, 1.6% of the total dose (Briggs 2015). Reports of adverse effects are rare. Avoid in suspected glucose-6-phosphate dehydrogenase deficiency.

Its very low oral bioavailability minimizes both the excretion in breast milk and the passage into plasma of the infant from ingested breast milk, except in the premature and in the immediate neonatal period in which there may be greater intestinal permeability.

Product with very few bibliographic and/or very old references, marketed in few countries.

See below the information of this related product:

  • Sulfathiazole (Moderately safe. Probably compatible. Mild risk possible. Follow up recommended. Read the Comment.)


Suggestions made at e-lactancia are done by APILAM team, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

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José María Paricio, founder of e-lactancia.

Other names

Phthalylsulfathiazole is also known as

Phthalylsulfathiazole in other languages or writings:


Main tradenames from several countries containing Phthalylsulfathiazole in its composition:


Variable Value Unit
Oral Bioavail. 5 %
Molecular weight 403 daltons


  1. Briggs GG, Freeman RK, Towers CV, Forinash AB. Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk. Wolters Kluwer Health. Tenth edition (acces on line) 2015

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